Certain container systems for storing and transporting liquids for biological or pharmaceutical applications include a container body with an elongated neck having an open mouth, a stopper formed from a resilient, pliable elastomeric material which is closely received at least partially within the mouth, and a cup-shaped cap which is secured over the mouth, such as by a screw connection, and retains the stopper on the container. The stopper can include an annular, radially-outwardly projecting flange which is captured between the inner surface of the cap and the distal end of the mouth when the cap is screwed down to prevent leakage. It is also known to provide an O-ring seal between the stopper and the mouth of the container, either between the outer diameter of the stopper and the inner diameter of the mouth, or between the axially-inwardly facing surface of the flange of the stopper and the distal open end of the mouth. The stopper can also have one or more radial ribs circumscribing the outer surface of the body of the stopper that sealingly press against the inner surface of the mouth.
The cap includes a central opening in its end, which enables flexible tubing to be inserted into through-holes in the stopper to enable liquid to be introduced and withdrawn from the container. During use, the liquid is introduced under aseptic conditions through a feed tube into a cleaned and sterilized container, with a vent tube enabling air within the container to escape. The tubes are then closed, a protective over cap is applied to the cap, and the container can be irradiated (if appropriate) and frozen for storage and transport. When it is desired to remove the contents of the container, the container is thawed, the tubes are opened, and the liquid is recovered.
The stopper, cap, tubing and container are typically formed of materials which are non-reactive to the liquids being stored and transported, and can withstand many of the typical operating conditions so that the contents of the container remain sterile and do not leak. Typical materials for the stopper include resilient thermoplastics and elastomers such as Thermoplastic Elastomers (TPE) or silicone. Typical materials for the tubing include TPE and silicone or equivalent, while typical materials for the container include plastic such as polycarbonate or polyethylene (e.g., Nalgene®), in a rigid (e.g., bottle-shaped) or flexible (e.g., a bag) form. The cap can be formed of a polymer such as plastic, elastomer, or other appropriate material.
One or more of the stopper, tubing, container and cap can be cleaned and reused if appropriate, but are typically disposed after a single use.
Such a container has received acceptance in the industry as being relatively simple to manufacture and assemble, inexpensive, and reliable as far as storing and transporting liquids.
Nevertheless, it has been found that during particularly low temperature storage and transport, such as when the container is stored and transported at temperatures between −70° C. to −120° C., the stopper can contract and enable liquid to leak from the container between the sides of the stopper and the neck of the container, up between the distal end of the mouth and the flange of the stopper, and between the flange and the inside surface of the cap. Such leakage can be undesirable, particularly when the container is cycled between low temperatures and ambient.
Thus, it is believed there is a demand for an improved container system, such as a container system which does not allow liquid to leak from the system during storage and transport at very low temperatures, and during cycling of the container between low temperatures and ambient.